1. Japanese Standards Association. JIS Z9101, Safety colours and safety signs; 1995.
2. American National Standards Institute. ANSI Z535.1, Safety color code; 2002.
3. ISO 3864-1, ISO/TC145/SC2. Graphical symbols—Safety colours and safety signs—part 1: Design principles for safety signs in workplace and public areas; 2002.
4. ISO3864 “Safety colours and safety signs” and revisions. Studies of Color 1997; 44: 2-14 (in Japanese with English summary).
5. A feature-integration theory of attention